The optical information recording medium such as a write-once type CD (hereinafter, abbreviated as “CD-R”), a write-once type DVD (hereinafter, abbreviated as “DVD±R”), a write-once type HD-DVD (hereinafter, abbreviated as “HD-DVD-R”), and a write-once type blu-ray disc (hereinafter, abbreviated as “BD-R”) has a structure in which a recording layer, reflection layer and cover layer, if necessary, are formed on one surface of a optical penetrating disc substrate. In addition, on one surface of the substrate in which the recording layer and reflection layer are formed, a screw or concentric-circle ditch, which is called “groove”, is formed, and a convex portion, which is called “land”, is formed between adjacent grooves. By irradiating the recording laser beam onto a recording layer on the groove of such an optical information recording medium by the optical information recording and playback apparatus, while carrying out the tracking along the ditch to form the recording marks, the recording is carried out. The playback is carried out by irradiating the regenerative laser beam onto the length nT (the cycle of the reference clock is T, and nT represents the length of integral multiple of T.) of the recording mark, the length nT of a portion (hereinafter, called space) between the recording mark and another recording mark and these arrangements to convert the reflection light to the regenerative signal.
As for CD-R and DVD-R, which are write-once type optical information recording mediums whose recording layer is made of the conventional organic dye, because the thermal reactivity of the used organic dye is favorable, the data recording is always kept to be favorable by applying a power condition in which the power is not outputted as much as possible in a region to form the space. Namely, for example, as depicted in FIG. 1, when a recording mark of 2 T (hereinafter, abbreviated as “P2T”) is formed, then a space is formed, and further a recording mark of 8 T (hereinafter, abbreviated as “P8T”) is formed, the level of a space forming power Ps, which is a power to form space, is equal to the level of a power Pc of a cooling pulse outputted immediately after the pulse of the write power Pw, which is the recording power to form the recording marks. Of course, a ratio εs of the space forming power Ps to the write power Pw is equal to a ratio εc of the power Pc of the cooling pulse to the write power Pw. Incidentally, when the recording mark P8T is formed by the multi-pulse type write strategy, plural pulses of the write power Pw are formed and after the respective pulses, a period is provided for which a bias power Pb is outputted.
However, as for HD-DVD-R and BD-R, which are the write-once type optical information recording medium for the bluish-purple laser, whose recording layer is made of the organic dye having the absorption spectrum at the wavelength λ=405 nm, it is known that the thermal reactivity of the organic dye is slower than that of the organic dye used for CD-R and DVD-R. On the other hand, in the writing to CD-R, DVD-R or the like, as depicted in FIG. 2, a strategy is adopted in which the remaining heat is given to a region to form the space after the cooling pulse whose pulse width dTs by applying the space forming power Ps whose value is greater than the power value of the power Pc of the cooling pulse and less than the power value of the write power Pw and the cooling pulse width dTs is provided, whereby the mark is easily formed.
JP-A-2006-48898 for HD-DVD-R and BD-R, which are the write-once type optical information recording medium for the bluish-purple laser, whose recording layer is made of the inorganic material having the absorption spectrum at the wavelength λ=405 nm, discloses a technique for forming a recording mark with high accuracy without causing heat interference between consecutive recording marks and cross-erasure between the recording marks in adjacent tracks or the like, onto a recording layer with high light transmittance such as an L1 layer of a double-layer optical recording medium. Specifically, when recording onto a semitransparent recording film with high light transmittance, a laser beam is pulse-modulated to emit a series of pulses including the write pulse of the recording power and the cooling pulse of a bottom power. After that, the recorded data is modulated to the length of the recording mark along the track of the recording layer, while the length of the recording mark corresponds to nT, which is an integral multiple of T, when one clock cycle is T. It is disclosed that this recording mark nT, which corresponds to nT, is formed by (n−1) write pulses, and when a recording mark equal to or longer than 4 T is formed, a cooling pulse whose pulse width is from 0.8 T to 2 T is inserted before the last write pulse. However, this publication is a document for the write strategy regarding the phase change recording of the inorganic material, and this document does not describe the write-once type optical information recording medium for the bluish-purple laser, whose recording layer is made of the organic dye having the absorption spectrum at the wavelength λ=405 nm.
Patent Document 1: JP-A-2006-48898